Closure

ABSTRACT

A closure formed from a material of relatively high flexibility and elasticity and having a sidewall defining a socket which is closed at one end by an integrally formed end wall. The closure may be utilized either as a plug for insertion in bores or cavities or as a cap for installation over the ends of pipes or rodlike objects.

United States Patent lnventor Joseph T. Miller St. Louis, Mo. Appl. No.802,131 Filed Feb. 25, 1969 Patented Apr. 13, 1971 Assignee Sinclair &Rush Inc.

St. Louis, Mo.

CLOSURE 1 Claim, 5 Drawing Figs.

US. Cl 138/96, 220/245, 138/89 Int. Cl F161 57/00, B65d 59/06 Field ofSearch 138/96, 96

Primary Examiner.lames Kee Chi Attorney-Gravely, Lieder & WoodruffABSTRACT: A closure formed from a material of relatively highflexibility and elasticity and having a sidewall defining a socket whichis closed at one end by an integrally formed end wall. The closure maybe utilized either as a plug for insertion in bores or cavities or as acap for installation over the ends of pipes or rodlike objects.

VPATENTEU'APRISISTI 3574312 Flc 4' z INYENTOR JOSEPH T. MILLER ATTORNEYSCLOSURE This invention relates in general to closures and moreparticularly to closures which are suitable for blocking different typesof openings.

In shipping machined parts having exposed threads the danger alwaysexists that the threads will become marred and rendered useless. Whenthe threads represent a port or the end of some fluid conduit on avalve, pump, or other type of fluid-conducting apparatus, the furtherproblem of protecting the interior of the apparatus from airbornecontaminants and rust-inducing moisture exists.

Heretofore, plastic closures in the form of plugs and caps have beendeveloped to economically alleviate these problems, but the closures ofcurrent manufacture have not entirely solved the problems and have insome instances compounded the problem. For example, most of the closuresof current manufacture are molded from polyethylene or polypropyleneplastisols, and these plastics are relative hard, possessing at most amoderate amount of flexibility and practically no elasticity.Consequently, when such closures are forced axially across threads,which is the only practical way to install them on a production linebasis, the hard plastic tends to shred and create the type ofcontaminants the closure is supposed to form a barrier against. Theshredding, in addition, reduces the effectiveness of the seal formedwith the threads. Furthermore, extremely close tolerances must be heldin the molding operation to insure that the closure does not fit tooloosely, in which case it will fall off of the threads, or too tightly,in which way to case an excessive amount of shredding occurs duringinstallation. In this connection, closures of current manufacture, byreason of their relatively inflexible and inelastic nature must besupplied in a different size for each standard female and male thread,and this, of course, complicates the maintenance of an adequateinventory. For example, to accommodate Winch, A-inch, inch, /-inch,ifs-inch and 1-inch pipe threads of both female and male fittings aninventory of l2 different conventional closures is normally required.

Moreover, the most common plastic closure plug is provided with anoutwardly projecting flange which overlies that portion of the structuresurrounding the threads into which the plug is inserted. This flangeprevents the plug from being inserted to too great a depth, but it alsomasks a portion of the structure so that when the structure is paintedor covered with a protective coating with the plug in place, anunpainted or unprotected ring remains at the surface masked by the plug.This ring can only be eliminated by a subsequent touchup operation.

Finally, by reason of their rigid construction, conventional caps andplugs are difficult to remove so as to expose the threads for subsequentuse. Normally, the closure is punctured with a screwdriver and thenpried away from the threads. Not

only is this a time-consuming operation, but it also produces shreddingsand chips which could damage or clog the structure the closure issupposed to protect from contamination. Furthermore, the screwdriver, ifmanipulated carelessly could mar the thread.

One of the principal objects of the present invention is to provide asingle closure which may be utilized either as a cap or a plug. Anotherobject is to provide a closure which does not shred when forced overthreads. A further object is to provide a closure which may be easilyremoved from the opening it closes. An additional object is to provide aclosure which forms a secure seal with threads and other surfaces whichdefine openings. Still another object is to provide a closure in theform of a plug which does not mask the I structure surrounding theopening into which it is inserted.

These and other objects and advantages will become apparent hereinafter.

The present invention is embodied in a closure engageable with generallycylindrical surfaces either as a plug or a cap. The closure has asocket-forming sidewall which is closed by an end wall. The inventionalso consists in the parts and in the arrangements and combination ofparts hereinafter described and claimed.

In the accompanying drawings which form part of the specification andwherein like numerals and letters refer to like parts wherever theyoccur:

FIG. I is a sectional view of a closure constructed in accordance withand embodying the present invention;

FIG. 2 is a plan view of the closure showing the open end of its socket;

FIG. 3 is an elevational view showing the mandrel used in the dippingoperation by which the closure is formed;

FIG. 4 is a sectional view showing the closure capping a pipe; and

FIG. 5 is a sectional view showing the closure plugging a threaded bore.

Referring now in detail to the drawings, 2 designates a closurepreferably formed from a substance which has a relatively high degree offlexibility and elasticity and resists shredding when fed along threads,knurls or roughened surfaces. Polyvinyl chloride (PVC) is one suchsubstance. The closure 2 integrally includes a circular sidewall 4(FIGS. 1 and 2) which closes upon itself or in other words is curvedabout a centerline extending through the center of the closure 2. Thecurved sidewall fonns a socket 6 in the closure 2, and merges at its oneend into a domed end wall 8 which closes one end of thesocket 6. Boththe inside and outside surfaces of the sidewall 4 taper, convergingtoward the end wall 8, and the taper of the inside is generally slightlygreater than the taper of the outside. The diameter of the inner wall issuch that it is slightly smaller than a conventional male thread,whereas the diameter of the outer wall is slightly larger than aconventional female thread. Thus, the sidewall 4 is sized for engagementwith at least two different types of threads.

At its opposite end, that is, the end opposite the end wall 8, thesidewall 4 merges into an outwardly flared flange 9 and an axiallydirected lip l0. The outwardly presented surface of the flange 9 isoblique to the outer surface of the sidewall 4 and to the central axisof the closure 2. The lip 10 extends axially from the end of the flange9.

Turning now to FIG. 3, the closure 2 is formed by dipping a mandrel 20into liquid polyvinyl chloride plastisol or some other suitableplastisol, and then removing the mandrel 20 and allowing the coating ofpolyvinyl chloride to cure into the closure 2. The mandrel 20 includesa'shank portion 22 which downwardly terminates at a beveled shoulder 24,the bevel of which corresponds to the bevel of flange 9. The shoulder24, in turn, merges into a nose portion 26 having a slight taper whichis generally equal to the taper of the inner surface on the sidewall 4.The diameter of the nose portion 26 is, furthermore, slightly largerthan the diameter of the inner surface on the sidewall 4. The noseportion 26 downwardly terminates at a domed end face 28.

The mandrel 20 is dipped into the liquid polyvinyl chloride plastisoluntil the tapered shoulder 24 is entirely submerged and the uppersurface of the liquid plastisol laps up onto the shank portion 22 alonga line S. After a predetermined time the mandrel 20 is withdrawn fromthe liquid plastisol and the coating adhering thereto is allowed to cureinto the closure 2.

Upon withdrawal of the mandrel 20 a small amount of polyvinyl chloridetends to run downwardly and accumulate at the lower end of the noseportion 26. This accounts for the fact that the taper of the innersurface of the sidewall 4 on the completed closure 2 is slightly greaterthan the taper of the outer surface. Once the coating has cured, theclosure 2 is peeled off and is ready for use. The diameter and taper ofthe nose portion 26 of the mandrel 20 is such that the socket 6 of thecompleted closure 2 will snugly accept a standard male pipe thread. Inaddition, the elasticity and flexibility of the plastisol, the taper ofthe mandrel 20, and the temperature of the mandrel 20 are all such thatthe outer surface of the sidewall 4 will be tapered and sufficient insize to snugly engage the threads of a standard female thread when theclosure 2 is forced therein. Thus, one closure 2 may be used on either astandard female or male thread. In this connection, the closure 2shrinks slightly upon being removed from the mandrel 20. andaccordingly, the exact size and taper of the nose portion 26 on themandrel 20 is calculated to accommodate nominal shrinkage.

In use the closure 2 may be used for capping the end of a pipe 20 (HO.4) having external threads 32. ln this sort of application the socket 6is aligned with the threaded end of the pipe 30, and thereafter theentire closure 2 is forced axially along the pipe 30 until the threadedend of the pipe 30 completely fills the socket 6. Since the closure 2 isformed from a flexible and elastic substance its sidewall 4 will expandslightly to accommodate the entrance of the pipe 30. Nevertheless, asthe inner surface of the sidewall 4 is forced across the threads 32 noshredding takes place and consequently the threads 32 are not cloggednor are loose shreddings introduced into the interior of the pipe 30.Once installed the closure 2, by reason of its elasticity, tightlyembraces the threads 32, forming a fluidtight seal therewith. In time,the material of the closure 2 experiences a slight amount of cold flow,so that the threads 32 actually embed within the sidewall 4, and thismakes the seal at the juncture of the two even more secure. Of course,the closure 2 may also be used to cap the ends of pipes or otherconduits or even rods which have no threads.

By reason of its flexibility and the presence of the flange 9 and lip10, the closure 2 is removed from the thread 32 of the pipe 30 as easilyas it installed. To remove the closure 2, it is gripped at its flange 9and lip 10 and either pulled or peeled backwardly off of the end of thepipe 30. Since the lip 10 extends entirely around the end of thesidewall 4 no special positioning of the closure 2 on the pipe 30 isnecessary to facilitate easy removal, as is the case with some closureshaving winglike tabs for effecting removal. Moreover, since the materialis flexible the flange 9 and lip 10 will deform in the presence ofnearby objects. By reason of the fact that the lip extends axially itwill not form an obstruction during packaging operations.

The closure 2 may also be used as a plug for blocking a conduit 34 (FIG.5) having a threaded bore 36. ln such an application the sidewall 4 isaligned with and forced into the threaded bore 36 with the end wall 8 ofthe closure 2 presented forwardly. The advancement of the large closures2 into corresponding bores 36 may be accomplished by inserting one'sthumb or finger into the socket 6 and pressing it against the end wall8, whereas in smaller sizes it is desirable to use a small rod having ablunt end for this purpose. In either case the application of the axialforce to the end wall 8 tends to elongate the sidewall 4 and furtherincrease its taper, thereby effecting easy installation. The closures 2may also be inserted into the bore 36 by applying the axial force at theflange 9. ln smaller sizes this can be accomplished by pushing with thethumb, whereas in larger sizes the flats of the fore and middle fingersshould be used. Advancement of the closure 2 into the threaded bore 36continues until the flange 9 engages that portion of the conduit 34which surrounds the bore 36.

During the advancement of the closure 2 into the conduit 34 the outersurface of the sidewall 4 passes across the threads of the bore 36without shredding, Furthermore, once the axial installing force isremoved the sidewall 4 tends to expand or back into the threads of thebore 36 forming a tight seal therewith, and this seal is improved duringthe course of time by the cold flow phenomenon previously mentioned.

Since the flange 9 does not project radially from the sidewall 6, but onthe contrary is oblique to the axial centerline of the closure 2, itdoes not lie flat against the outer surface of the conduit 34 andthereby mask it as is true of the flanges on some conventional plugs.Consequently, the outer surface of the conduit 34 may be painted up tothe margin of the threaded bore 36 with the closure 2 in place.

The closure 2 is removed from the bores 36 merely by grasping it alonspecific size as a plug and the male thread of that same size as a cap,with some exceptions at smaller sizes, For example, it has been foundthat a single closure 2 will accommodate both l-inch NPT female and malefittings as a cap and plug, respectively and the same applies to 54-inchNPT and 52-inch NPT fittings, only with smaller closures 2. Still asmaller closure 2 will serve as a cap for A-inch and %-inch NPT fittingsand as a plug for %-inch NPT fittings. Yet another closure 2 willaccommodate /ti-inch NPT male fittings and 56- inch NPT female fittings.Finally, an even smaller closure 2 may be used as a plug for rs-inch NPTfittings. Thus, for the l2 different conventional threads found of pipefittings between and inclusive of Va-inch and l-inch NPT, an inventoryhaving only six closure sizes is required to close any one of them. Thesame closures may also be used with other threads of similar sizes, andthey are not restricted to pipe threads. For example, the closure 2which fits female and male l-inch NPT fittings will also fit male andfemale standard threads of l 3/ 16-inch, Wa-inch and l 5/l6-inchdiameter.

This invention is intended to cover all changes and modifications of theexample of the invention herein chosen for purposes of the disclosurewhich do not constitute departures from the spirit and scope of theinvention.

lclaim:

A protective closure for installation at the end of a generallycylindrical surface; said closure comprising a wall of annularcross-sectional shape and having generally cylindrical inwardly andoutwardly presented surfaces, both the inwardly and outwardly presentedsurfaces being substantially smooth and continuous and each being lip toengage a different generally cylindrical surface of standard size; anend wall connected to and formed integral with one end of the sidewall,the end wall extending across and closing the area circumscribed by theend of the sidewall, whereby the sidewall and end wall form a socket inthe closure; a continuous flange connected to and formed integral withthe opposite end of the sidewall and extending completely around end ofthe sidewall, the included angle between the sidewall and the flangebeing greater than and the flange being presented obliquely with respectto the axial centerline of the sidewall, the flange further beinglocated in its entirety radially beyond the inwardly presented surfaceof the sidewall, whereby it does not interfere with the insertion ofobjects into the socket formed by the sidewall; and a lip connected toand formed integral with the flange at the outer end of the flange, thelip extending completely around the flange at the outer end thereof andprojecting generally axially away from the end of the sidewall to whichthe flange is attached, the lip further having its inwardly presentedsurface located further from the axial centerline that the inwardlypresented surface of the sidewall; the closure being formed in itsentirety from a flexible elastomeric material so that it deforms easilywhen subjected to localized forces, said lip being deformable toward theend of said cylindrical surface; the closure further affordingprotection to generally cylindrical surfaces interchangeably in one oftwo circumstances, the first circumstance being when the generallycylindrical surface to be protected and closed is engaged by theoutwardly presented surface of the sidewall and the end wall serves as aplug, in which case the flange and the lip are spaced from the end ofthe cylindrical surface and the lip is presented axially outwardly fromsaid end for easy gripping, and the second circumstance being when thegenerally cylindrical surface to be protected is engaged by the inwardlypresented surface of the sidewall and the end wall serves as a cap, inwhich case the lip will be presented in diametrically outwardly spacedrelation to the generally cylindrical surface for easy gripping.

Patent No.

Inventofls) UNITED STATES PATENT OFFICE Dated 5 3 191 Joseph T. MillerIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column Column line line

"forced".

Column (mitt) attest:

line

line

line

line

line

30, after "in which" cancel "way to".

19, after when cancel "fed and substitute 4? after "of" insert "the".

34 cancel "lip" and substitute "sized".

41, after "around" insert "the".

64 cancel "the" I T'Zigped and. sealed V this 26th day of October 19'5"was???" (ifi'rmarzimx ting Jommisaiomw of Patents

1. A protective closure for installation at the end of a generallycylindrical surface; said closure comprising a wall of annularcross-sectional shape and having generally cylindrical inwardly andoutwardly presented surfaces, both the inwardly and outwardly presentedsurfaces being substantially smooth and continuous and each being lip toengage a different generally cylindrical surface of standard size; anend wall connected to and formed integral with one end of the sidewall,the end wall extending across and closing the area circumscribed by theend of the sidewall, whereby the sidewall and end wall form a socket inthe closure; a continuous flange connected to and formed integral withthe opposite end of the sidewall and extending completely around end ofthe sidewall, the included Angle between the sidewall and the flangebeing greater than 90* and the flange being presented obliquely withrespect to the axial centerline of the sidewall, the flange furtherbeing located in its entirety radially beyond the inwardly presentedsurface of the sidewall, whereby it does not interfere with theinsertion of objects into the socket formed by the sidewall; and a lipconnected to and formed integral with the flange at the outer end of theflange, the lip extending completely around the flange at the outer endthereof and projecting generally axially away from the end of thesidewall to which the flange is attached, the lip further having itsinwardly presented surface located further from the axial centerlinethat the inwardly presented surface of the sidewall; the closure beingformed in its entirety from a flexible elastomeric material so that itdeforms easily when subjected to localized forces, said lip beingdeformable toward the end of said cylindrical surface; the closurefurther affording protection to generally cylindrical surfacesinterchangeably in one of two circumstances, the first circumstancebeing when the generally cylindrical surface to be protected and closedis engaged by the outwardly presented surface of the sidewall and theend wall serves as a plug, in which case the flange and the lip arespaced from the end of the cylindrical surface and the lip is presentedaxially outwardly from said end for easy gripping, and the secondcircumstance being when the generally cylindrical surface to beprotected is engaged by the inwardly presented surface of the sidewalland the end wall serves as a cap, in which case the lip will bepresented in diametrically outwardly spaced relation to the generallycylindrical surface for easy gripping.